Every circle of friends has one—the guy who's only willing to chip in "a couple of bucks" for the night's keg but double fists his brews the entire evening. Well, no longer! This suds security system will only pour for authorized imbibers.

Members of the Milwaukee Hackerspace integrated the system to a converted kegerator (it used to be a normal refrigerator). Using an Arduino board and RFID reader, the tap will only unlock after a user swipes an RFID authorization fob. The system also records how many times each fob is swiped, letting you keep an eye on who'll most need a cab at the end of the evening. [Build Lounge via Hack A Day]